The view of the south side of G. Benarat from Camp 5, in the Melinau Gorge is almost as quintessentially Mulu as the bat flight and Abraham Lincoln’s outline in Deer Cave. For anyone gazing across the river at Benarat, as almost every photograph will testify, the gaping black entrance of Tiger Cave is impossible to miss. For the 1978 explorers, the sight of this huge cave underlined the fact that it wasn’t just G.Api that was riddled with holes - Benarat had its own selection of secrets, too.

Back in 1978, when Camp 5 was originally established, two of the cave explorers fought their way through the forest to the base of the Benarat cliff in the hope of finding an easy climbing route up to this enticing entrance. However, as is the way with Mulu cave exploration, their attention was drawn away from the climb towards a small, strongly draughting hole at the base of the cliff.

Crawling along a small tube, past an equally nervous cave racer snake, the cavers found themselves in a short maze of pitches, avens and steep passages. Although they were aware that the strong draught had to come from somewhere deeper within the mountain, their few caving trips into this new cave ­ Tiger Foot Cave - didn’t reveal the route onwards.

On a return trip in 1980 a breakthrough was made - a caver climbed a ramp and to his great surprise popped his head up into the floor of a large passage. Benarat Highway had been discovered and the cave was renamed ­ Benarat Caverns.

The survey of Benarat Highway looks almost like a gun barrel, heading halfway through the mountain. Unfortunately for cavers, the reality is very different for the entire passage is floored with a combination of fallen blocks, steep sediment banks and crunchy sharp calcite. It took many exploratory trips to reach the far end of the cave where calcite choked any hope of a way on.

During the exploration, the cavers camped at Barking Dog Junction ­ so named because of the noise produced by a loud drip. From here, a large side passage, Homeward Bound, completed a full U turn and headed back towards the Melinau Gorge. Unfortunately, this passage didn’t obligingly pop out on the side of the Melinau Gorge, as had been predicted, but appeared to end in a large underground chamber only a few metres inside the face of the cliff.

It wasn’t until 2003 that a connection was eventually made to Homeward Bound from the Melinau Gorge. Over a series of visits, a hardy band of cavers with a yearning for the small caves of their native Yorkshire in the UK, used hammers and chisels to chip a small, flat-out crawling route over calcite to break into a passage which emerged over the final chamber in Homeward Bound.

Despite its very linear appearance, Benarat Caverns has some unusual vertical inclinations. In the heart of the cave there are some extraordinary large and deep pits which, to their original explorers, looked very inviting. But despite long, reverberating echoes, these shafts, one greater than 100 metres deep, all closed up amongst walls of mud and there were no booming passages leading away.

The large shafts didn’t only head down - SuperRamp, off Homeward Bound, went up and up and up... In 1984, this massive ramp was climbed for 150 metres and, in 2000, another team reached a height of 230 metres above the passage floor. Despite all their efforts, an examination of the roof above this point showed that there was no clear passage leading off from the top!

To the west of Barking Dog Junction a small passage suddenly emerges in the wall of a very large chamber ­ The Big Mistake. In 1984 the original explorers simply thought that they had dropped into yet another deep blind pit, but 21 years later in 2005, they were proved wrong. In the opposite wall of the chamber was another passage and the explorers of Moon Cave emerged through this to confirm the link with Benarat Caverns.